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121.
作者1987年于四川省乐山市大渡河尾段发现椎实螺属一新种,现命名为乐山椎实螺(Lymnaea leshanensis sp.nov.)。该种与日本琵琶湖产的 Lymnaea onychia 相似,但贝壳的形态、齿式、齿形、两性生殖系统的诸器官、外套膜的色带、个体大小、生活环境和动物区系均有所不同。前者属东洋区系,后者属古北区系。 相似文献
122.
Xie Simei Hao Chunjiang Zou Bin Jing Qiyi Liao Xiaohong Sheng Xiaowen Zhang Canrong 《海洋学报(英文版)》2000,19(1):35-46
INTRODUCTIONTheSMSRPSisstalledontheshipnavigatingovertheseaandreceivessatellitecloudmapsatanytimetoprovidereliablereal-timedataofmeteorologyandocean.Itisanimportantequipmentforsafeguardofshipnavigation.Chinahasthousandsofoceanicships.Butalmostallships,withonlyveryfewexception,arenotstalledbySMSRPS.Thecausesareasfollows:1.Thetechniqueisverycomplicated.2.Thedevelopmentcostisveryhigh.3.Ifweintroduceforeignequipment,thecostistooexpensive.4.Foreignequipmentanditssoftwarearecompletelyclo… 相似文献
123.
An experimental set-up is developed and proved to be effective for laboratory study of an underwater towed system. The experimental technique gives a practical method for monitoring the kinematic and dynamic performance of an underwater towed system in a ship towing tank. Both the theoretical and experimental results in the investigation indicate that the hydrodynamic response of a towed vehicle to the wave induced motion of a towing ship can be significantly reduced by applying a two-part tow method. A comparison of the numerical and experimental results in the investigation demonstrates that the numerical simulation results are close to the experimental data, overall agreement between experimental and theoretical results is satisfactory. The results qualitatively verify the mathematical model of a two-part underwater towed system proposed by Wu and Chwang [Wu, J., Chwang, A.T., 2000. A hydrodynamic model of a two-part underwater towed system. Ocean Engineering 27 (5), 455–472]. 相似文献
124.
苏北盐城凹陷复合含油气系统 总被引:1,自引:0,他引:1
苏北盐城凹陷含油气系统可划分为上、下2个复合含油气系统。上复合含油气系统,即Pz、K2p、K2t(生)-K2t、E1f1(储)一E1f1 E1f2(盖),古生界、中生界浦口组和泰州组为烃源岩层,泰州组和阜宁组一段为储集层,阜宁组一段顶部至二段暗色泥岩为区域盖层,油气沿深大断裂运移,油气成藏关键时刻在古近纪晚期至新近纪早期,有利勘探区在深大断裂附近的中、新生界发育地区;下复合含油气系统,即Pz、K2p(生)-Pz、K2p(储)-K2p3 K2p4(盖),油气通过断层或不整合运移,油气大量生成的关键时刻为古近纪早期,该系统中气藏分布在古生界被中生界覆盖地区。 相似文献
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数字地球与海洋科学的发展 总被引:3,自引:0,他引:3
本文从数字地球的概念出发,根据海洋科学的发展要求,详细论述了数字地球与海洋科学的发展关键。并提出了海洋科学的新的发展战略和配套技术的开发研究理论,从而为我国海洋事业的发展和数字地球的建立有一个协调和统一的认识观点。 相似文献
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129.
This study takes cognizance of the fact that the TIOMIN (TIOMIN Resources Inc. of Canada) project has resulted in controversy over its handling of environmental issues and especially the Environmental Impact Assessment (EIA). The authors address many of the protracted issues that have slowed the development of the mining project in Kwale. The main emphasis is on the impacts of the mining and mineral separation processes on the environment, including the governing legislation, the role of consultation and public participation, and socioeconomic issues. In their public documents TIOMIN has specified neither the type of minerals it wants to extract from the area nor their chemical composition. It is well known, however that the titanium minerals and zircon targeted have impurities of iron, thorium and uranium. In the absence of an Environmental Management Plan, the effects of stockpiling radioactive wastes and other impurities that could possibly lead to environmental degradation in both the terrestrial and marine environments have not been publically addressed. The measures proposed to mitigate ecological damage as a result of the establishment of a minerals processing plant in the area seem inadequate. Pollution resulting from accidental spillage or breakage could have significant impact on marine life and residents living near the mining site. Other issues that have not been addressed satisfactorily pertain to the use of surface and underground water. The area already faces a huge water deficit and the calculations presented on aquifer recharge and stream flow rates do not indicate the large quantities of water that would be required in the mineral processing plant. The project, if approved in its present state, risks violation of international conventions. Furthermore, it could cause a conflict between Kenya and Tanzania in the event of an oil spill at the proposed ship loading facility at Shimoni. The proposed mining area includes the district's most fertile land, is home to many fisherfolk and is a major tourist destination. An analysis of the effects of this project on other available opportunities must be thoroughly understood to ascertain the economic and environmental benefits and costs of the mining venture. The proposed compensation rate of $1,000 per acre, for resettlement for example, appears to be grossly inadequate. Compensation should take into account family size and structure family assets and the cost of relocation. 相似文献
130.
The accurate prediction of extreme excursion and mooring force of floating offshore structures due to multi-variete environmental conditions which requires the joint probability analysis of environmental conditions for the worst case situation is still impractical as the processing of large amount of met-ocean data is required. On the other hand, the simplified multiple design criteria (e.g. the N-year wave with associated winds and currents) recommended by API known as traditional method does lead neither to the N-year platform response nor to the N-year mooring force. Therefore, in order to reduce the level of conservatism as well as uncertainties involved in the traditional method the response-based method can be used as a reliable alternative approach. In this paper this method is described. In order to perform the calculations faster using large databases of sea states, Artificial Neural Networks (ANN) is designed and employed. In the paper the response-based method is applied to a 200,000 tdw FPSO and the results are discussed. 相似文献